Definbe extra allowable COFF section flags for ARM_PE target/

bfd/coff-arm.c

@@ -2536,11 +2536,13 @@ coff_arm_final_link_postscript (abfd, pfinfo)
 #define TARGET_UNDERSCORE 0
 #endif
 
+#ifndef EXTRA_S_FLAGS
 #ifdef COFF_WITH_PE
 #define EXTRA_S_FLAGS (SEC_LINK_ONCE | SEC_LINK_DUPLICATES)
 #else
 #define EXTRA_S_FLAGS 0
 #endif
+#endif
 
 /* Forward declaration for use initialising alternative_target field.  */
 extern const bfd_target TARGET_BIG_SYM ;